Tow ejector



Feb! 11, 1969 w. s. MCCASKILL ET AL 3,426,630

TOW EJECTOR Sheet Filed Sept. 6, 1966 Feb, 11, 6 w. B. MCCASKILL. :ET AL 3,426,630

TOW 'EJECTOR Shet Filed Sept. 6, 1966 F llll Feb. 11, 1969 w. a. MCCASKILL ETAL TOW EJECTOR Filed Sept. 6, 1966 Sheet r-n I 7D "& @IL

United States Patent 3,426,630 TOW EJECTOR William Brand MeCaskiil, Waynesboro, Va., and James Preston Neal IV, Newburgh, N.Y., assignors to E. I.

du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware Filed Sept. 6, 1966, Ser. No. 577,261

US. CI. 83-66 Int. Cl. B2611 /38, 7/06 5 (Ilaims ABSTRACT OF THE DISCLOSURE The present invention is concerned with the production of staple libers. It is particularly concerned with the operation of cutting continuous fibers into staple fibers. It is more particularly concerned with apparatus for removing the tow from the cutter when the tow feed is interrupted, to avoid fusing the fibers.

One common method of cutting continuous filaments into staple makes use of the Beria cutter first described in US. Patent 1,723,998 and on which many improvement patents were later issued. This cutter includes a disk having an axial entry for the rope or tow of yarn and a radial outlet through which the tow emerges as the disk is rotated at high speed. The emerging tow strikes a knife edge and is cut off at each revolution of the disk. However, if the tow feed is interrupted for any reason, the end of the tow in the disk becomes heated and filaments are fused together and some of these are subsequently mixed with the other staple. These fused fibers cause difiiculties in carding and spinning operations and result in non-uniform yarns.

It is, therefore, an object of the present invention to provide apparatus for removing the tow from the cutter in case of interruption of tow feed. It is a further object to provide apparatus which will remove the tow from the cutter at a preferred time interval from the time the tow feed ceases. It is a still further object of this invention to provide apparatus that will remove the tow from the cutter at a proper time interval from the time of interruption of tow feed, and which apparatus will then, after a suitable further interval, return to its start-up position.

These objects are accomplished in the present invention by an air cylinder and piston and a series of delayed action pneumatic or electrical relays which become energized when the tow feed is interrupted for a minimum time interval, and the piston rod pulls or pushes the tow from the cutter. After a proper further time interval, the apparatus returns to its normal position from the single energizing action.

A drawing of a modern version of a Beria cutter is shown in US. Patent 3,161,100 to Resor. The disk of this machine, through which the tow is fed, rotates at high speeds which create considerable friction against the tow. Occasionally the tow feed is stopped automatically by knots or for some other reason. In the past it has been necessary to have an operator at hand at all times to remove the tow from the cutter in case of stoppage, or to "ice risk contamination of the cut staple with fused fibers. Knots in the tow is a common cause of stopping the tow.

The present invention is best understood by referring to the attached drawings.

FIGURE 1 is a schematic drawing showing normal operating conditions in the cutting of tow.

FIGURE 2 shows the conditions after the tow feed has stopped and the tow end has been pulled from the cutter disk by the apparatus of the present invention.

FIGURE 3 is a more detailed drawing of one embodiment of the invention.

FIGURE 4 is a schematic drawing of one type of apparatus of the present invention in which pneumatic devices are used for delayed responses to tow feed stoppage.

FIGURES 5 and 6 are schematic drawings of another version of the present invention in which electrical devices are used for delayed responses to tow feed stoppage.

FIGURE 1 shows the tow 10 during normal cutting traveling from right to left into the cutter 12, pulled by disengageable pull rolls 14. 16 is an air cylinder containing a piston 18 connected to a rod having a right angle extension 20 over which the tow passes. A brake is shown at 22. Simultaneously, when tow feed stops, the pull rolls 14 separate to allow the tow to be pulled from the cutter and brake 22 is activated. Three to live seconds later, piston 18 is activated so that rod extension 20 engages the tow 10 and withdraws it from the cutter.

FIGURE 2 shows the conditions about 3 to 5 seconds after tow feed has ceased. The piston 18 has moved to the opposite end of the cylinder 16 and the arm 20 on the piston rod has pulled the end of the tow 10 from the cutter 12. The pull rolls 14 are shown separated and brake 22 is shown clamping the tow 10.

FIGURE 3 shows greater detail of these elements and a slight modification of the withdrawing means. Disengageable pull or feed rolls 14 are held together by a second air cylinder 24 and piston 26 with air pressure. When the system is energized due to the passage of a knob or other interruption, cylinder 24 is vented on the pressure side and air is applied on the opposite side of piston 26 to force the shafts of the rolls 14 apart. This occurs immediately upon stoppage of tow .10 so that the withdrawal means (rod extension 20 in FIGURE 1) can function. Braking means 22 is provided so that, upon stoppage of the tow 10, the tow may be withdrawn from the cutter 12 and not from the feed source. During normal operation, brake 22 is disengaged. Upon stoppage of the tow, a third air cylinder 28, operated in the same manner as cylinder 26', is immediately activated to engage the brake 22. FIGURE 3 also shows a slight modification of tow ejector cylinder 16. "In this figure, rod extension 20 of piston 18 pushes the tow, rather than pulls as in FIGURES 1 and 2, upon activation of tow ejector cylinder 16 three to five seconds after stoppage of tow 10. When various interruptions in tow feed occur, the system can be energized automatically or manually as desired. For example, in FIGURE 3, tow 10 is passed through rollers 30 and there is a flip switch 32 operated by one of the rollers so that when a knot goes through the rollers 30, the switch 32 is flipped, the pull roll motor is shut oil, and the relays are energized. This occurs in normal operation because a knot is tied in the end of the tow since, if the tow ran through the cutter 12 to the end, there would be long fibers in the cut staple. Of course, if desired, an operator could do the same thing by pushing a stop button. For safety purposes, a guard (not shown) is placed over pull rolls 14. If this guard is lifted, it automatically stops the tow and energizes the system in a similar fashion. Once the knot switch 32 or other sensing means is tripped and the feed roll motor is stopped, a standard air solenoid valve supplies air to the cylinders, 24 and 28, engaging the brake 22 and disengaging the feed rolls 14. After a slight delay of at least about three to five seconds, the tow ejector cylinder 16 is activated as discussed more fully below to pull the tow out of the cutter 12.

FIGURE 4 shows pneumatic actuating means for operating the tow ejector cylinder 16. This apparatus operates as follows: The solenoid 34 is energized when tow feed ceases and the motor powering the pull roll stops. This allows air to flow from the pressure control valve 36 at 25 pounds pressure through flow control valve 38 to relays 40 and 42. After at least about 3 to 5 seconds, these relays are tripped and air flows to relays 44- and 4 6 from pressure control valve 48 at 25 pounds pressure. Relays 44 and 46 are tripped, relay 44 allowing air to enter the bottom of cylinder 16 from pressure control valve 50 at 60 to 80 pounds pressure and raising piston -18 and rod arm 20 over which the tow It) lies as shown in FIGURE 1. Relay 46 allows air in the top of the cylinder 16 to vent through 52.

Five seconds after relay 42 trips, relay 54 trips venting the line and releasing pressure from relay 44. Relay 46 is pressurized and piston 18 is forced down to its original, nonmal position. Relays 54 and 42 have their vents plugged at 56 and 58, respectively. Return of piston 18 to its original position is essential to restarting normal operation.

The tripping of relays 40 and 42 after 3 to 5 seconds, as described above, is achieved by using an electrical relay which consists of a bellows having an orifice whose size determines delay time. The bellows is normally under pressure and when energized, the vent is opened. When pressure decreases, a solenoid valve opens the air valves. The vent from the air bellows is adjustable to any time from O to 60 seconds. The preferred 3 to 5 second delay is not a critical one, but is convenient so that in starting up, the operator can jog the machine for a fraction of a second to pull the tow back to the cutter with a startstop button without again tripping the relays. As long as the start-stop operation is less than 3 to 5 seconds, the tow 10 can be fed back to the cutter 12 without having it immediately pulled out again. Then the on button can be pushed and the cutting operation begun again. Thus, if the delay time were only 1 to 2 seconds, the tow withdrawing means might activate again before startup could be accomplished.

The solenoid, pressure control valves, flow control valves are all conventional and individually are not contended to be patentable. The invention resides in the novel combination of these elements.

FIGURES 5 and 6 present another version of the invention in which a delayed action electrical relay system is used instead of pneumatic devices. This apparatus operates as follows:

TD-1 (normally closed) and TD-2 (normally open) are electrical time \delay relays. These relays contain a normally compressed rubber bellows with an adjustable orifice at the bellows inlet. The orifice size determines the time necessary for the bellows to completely expand and for the relay contacts to open or close. The bellows is filled with ambient air. The coils for each of these relays is connected in parallel with the feed roll motor on the Beria type cutter. The relay contacts are connected in parallel across all the interrupting devices of the pull roll motor (start-stop button, knot switches, roll guard, etc.) and in series with the four-way air solenoid valve 60. The sequential operation is:

The feed roll motor is stopped by any of the interrupting devices previously mentioned.

Three seconds (time is adjustable) after the pull roll motor is de-energized, the contacts on TD-2 close energizing the four-Way air solenoid valve 60 (reversing the normal position of the solenoid valve and providing pressure to line A while exhausting line see FIGURE 6). Cylinder rod 20 is extended.

Seven seconds (time is adjustable) after the pull roll motor is stopped (or four seconds after TD-2 closes) TD-l opens, returning the air solenoid valve to its original position (pressure to line B and line A to exhaust portsee FIGURE 6). Cylinder rod is retracted.

Cycle is completed.

When the pull roll motor is started, the time delay relay contacts return to their original position.

It should be noted that the solid-lined part of the circuitry of FIGURE 5 is equally adaptable to either the pneumatic or electrical system to give added flexibility.

The use of this invention has eliminated the occurrence of fused fibers in cut staple caused by rotor fusion. It has also removed the necessity of having an operator constantly at or near each machine to remove the tow manually in case of the interrupted tow feed.

Further, as discussed above, the 3 to 5 second delay in pulling the tow from the critter in case of shut down is desirable in connection with restarting the machine. During stringup or startup, the pull roll switch is joggled to pull through enough tow to reach to the cutter and to start it feeding into the cutter. If there were no delay on the first relays, then the tow would be pulled out of the cutter immediately. Since the joggling requires less than 3 to 5 seconds, the machine can be strung up and started without setting in motion all the mechanisms leading to pulling the tow from the cutter.

It should be obvious that the air cylinder can operate with the pull rod above or below the cylinder. Whether the pull rod is above or below the cylinder will depend upon the most available space for it. The pull rod may pull or push the tow.

Various other modifications may occur to those skilled in the art without departing from the spirit of this invention or the scope of the appended claims.

What is claimed is:

1. Improved apparatus for cutting continuous fibers into staple fibers comprising in combination:

(A) rotary cutting means adapted to receive and cut continuous fibers;

(B) disengageable feed means in advance of said cutting means adapted to receive and advance said continuous fibers during normal operations;

(C) interruptible drive means for driving said feed means during normal operation;

(D) braking means in advance of said feed means adapted to engage said fibers when activated;

(E) reciprocal withdrawal means, intermediate said feed means and braking means, adapted to sequentially withdraw said continuous fibers from said cutting means and return to its initial position when activated;

(F) sensing means for sensing irregularities in the fiber during its advance;

(G) first activating means operably connected to be responsive to said sensing means to substantially simultaneously disengage said feed means, interrupt said drives means and activate said braking means upon sensing an irregularity; and

(H) second activating means operably connected to be responsive to said sensing means to activate said withdrawal means at a predetermined interval after sensing an irregularity.

2. Claim 1 wherein said second activating means activates said withdrawal means at least 3 to 5 seconds after the sensing of an irregularity.

3. Claim 1 wherein said reciprocal withdrawal means comprises an air cylinder having an activatable piston with an extension positioned to operatively engage said continuous fibers upon activation of said piston.

4. Claim 1 wherein said second activating means is a delayed action pneumatic relay system.

5. Claim 1 wherein said second activating means is a ANDREW R. JUHASZ, Primary Examiner.

delayed action electrical relay system.

References Cited UNITED STATES PATENTS C1- X.R.

5 2,424,555 7/1947 Curtis 83403 X 83362, 367, 403 2,722,983 11/1955 Gibson et a1. 83-403 X FRANK T. YOST, Assistant Examiner" 

